:root {
  color-scheme: light dark;
  --fg: #1a1a1a;
  --bg: #ffffff;
  --muted: #666666;
  --border: #d0d0d0;
  --accent: #2563eb;
  --accent-fg: #ffffff;
  --error: #dc2626;
}

@media (prefers-color-scheme: dark) {
  :root {
    --fg: #e8e8e8;
    --bg: #121212;
    --muted: #999999;
    --border: #3a3a3a;
    --accent: #60a5fa;
    --accent-fg: #0a0a0a;
    --error: #f87171;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--fg);
  background: var(--bg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
    "Hiragino Kaku Gothic ProN",
    "Noto Sans JP", sans-serif;
  line-height: 1.6;
}

main {
  max-width: 640px;
  margin: 0 auto;
  padding: 2.5rem 1.25rem 3rem;
}

h1 {
  font-size: 1.5rem;
  margin: 0 0 0.5rem;
}

header p {
  color: var(--muted);
  margin-top: 0;
}

a {
  color: var(--accent);
}

section {
  margin-top: 2rem;
}

label {
  display: block;
  font-weight: 600;
  margin: 1.25rem 0 0.375rem;
}

textarea {
  width: 100%;
  padding: 0.625rem;
  color: var(--fg);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.9rem;
  resize: vertical;
}

textarea[readonly] {
  background: color-mix(in srgb, var(--bg) 92%, var(--fg));
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

button {
  padding: 0.5rem 1rem;
  font-size: 0.9rem;
  border: 1px solid var(--accent);
  border-radius: 6px;
  background: var(--accent);
  color: var(--accent-fg);
  cursor: pointer;
}

button.secondary {
  background: transparent;
  color: var(--fg);
  border-color: var(--border);
}

button:hover {
  opacity: 0.9;
}

button:active {
  opacity: 0.8;
}

#status {
  min-height: 1.2em;
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: var(--muted);
}

#status[data-state="error"] {
  color: var(--error);
}

footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--muted);
}